Functionalized Separator Coating for Lithium Dendrite Suppression
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Solution Overview
Problem
Lithium metal batteries are prone to lithium dendrite formation during charging, leading to reduced coulombic efficiency, cycle life, and safety risks due to internal short circuits.
Innovation Solution
A functionalized separator with a porous substrate and a functional film layer containing inorganic particles that reversibly react with lithium to form a lithium alloy, inhibiting dendrite growth and improving deposition/dissolution behavior of lithium ions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional separator is used in lithium metal batteries, then the battery structure is simple and easy to manufacture, but lithium dendrites form during charging leading to reduced coulombic efficiency, cycle life, and safety
Solution Approach 1:
The separator is constructed as a composite material system consisting of a porous substrate (polyolefin or ceramic) coated with a functional film layer containing inorganic particles (silicon, germanium, tin, or their oxides). This composite structure enables the separator to reversibly react with lithium dendrites, improving coulombic efficiency and cycle life while maintaining structural integrity
Solution Approach 2:
The separator employs a porous substrate structure with specific pore size distribution that allows lithium ion transport while providing mechanical support. The porous structure is coated with functional film containing inorganic particles that can reversibly alloy with lithium, combining the advantages of ion conductivity with dendrite inhibition capability
2Object-affected harmful factors
If no functional film layer is added to the separator, then the manufacturing process is simple, but lithium dendrites can penetrate through the separator causing internal short circuits and safety accidents
Solution Approach 1:
The functional film layer is pre-formed on the separator surface before battery assembly. This preliminary action creates a protective barrier that can reversibly react with lithium dendrites before they can penetrate through the separator, preventing internal short circuits and safety accidents
Solution Approach 2:
The functional film layer acts as an intermediary between the separator and lithium dendrites. The inorganic particles in the film (silicon, germanium, tin, or their oxides) serve as mediators that reversibly alloy with lithium, intercepting dendrite growth and preventing direct penetration through the separator
3Reliability
If the inorganic particles have small particle size (10 nm to 200 nm), then the surface area for lithium alloying reaction is increased improving dendrite inhibition, but the manufacturing precision and uniformity of the functional film layer become more difficult to control
Solution Approach 1:
The patent specifies optimal particle size ranges (10 nm to 200 nm, preferably 50 nm to 100 nm) that balance dendrite inhibition effectiveness with manufacturability. This parameter optimization ensures sufficient surface area for lithium alloying reaction while maintaining uniform distribution and adhesion in the functional film layer during manufacturing
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances initial coulombic efficiency, cycle performance, and safety by controlling lithium deposition, preventing dendrite penetration, and maintaining stable lithium ion transmission.
Implementation Method 1
the functional film layer comprises inorganic particles which are able to reversibly react with metal lithium to form a lithium alloy
Implementation Method 2
the polymer coating layer comprises a group that is reversibly bonded with lithium ions. The group reversibly bonds with lithium ions by reacting with the lithium alloy
Implementation Method 3
the group in the coating layer may form chemical bond in suit with lithium ions, wherein the chemical bond may serve as a channel for transmitting lithium ions
Data Source
AI summary
The present application discloses a functionalized separator, a method for preparing the same, a lithium metal battery, and a device comprising the lithium metal battery. The functionalized separator comprises a porous substrate and a functional film layer provided on at least one side of the porous substrate, wherein the functional film layer comprises inorganic particles which are able to reversibly react with metal lithium to form a lithium alloy.